After finishing my first down quilt, I think I should move the 3/4 under quilt I was planning to the top of my project list instead of the mosquito net hammock that I was going to make next.

My hammock is a simple Speer type hammock with whipped ends. Since I used an under quilt for the first time last night, I have a lot of questions. Any advice would be greatly appreciated.

How wide should I make the quilt?

Should the baffles run length-wise, or accross?

For a quilt about 54"-60" long, will the ends have to be cinched up to make it conform to the hammock?

Should there be a channel for a drawcord suspension along the length of the quilt, so the quilt can be slid into position along the length of the hammock?

Or, would it be better to add loops on the side of the hammock from which to suspend the quilt?

For length-wise baffles, would it be a good idea to put less down on the sides and more in the center chambers?

Has any ultra-lighter figured out a second purpose for a 1/2 or 3/4 UQ aside from a kilt?

I am hoping to come in at around 12-14oz for the quilt with a 3" loft. I use a small 20"x20" sit pad anyway as a pack frame, and I am planning to use it for my feet. Of course, it's always a bit of a compromise between comfort and weight, but I am leaning more towards comfort and plan to make it at least 54" long. The quilt will replace a Thermarest Prolite-4, so between it and the SPE wings I have got 19oz at the moment. Anything under that for the same warmth and more comfort and I'll be happy.

02-24-2008, 19:11

Just Jeff

1 - 45-48" wide
2 - Either way works
3 - Yes
4-5 - Either way works. Shockcord running thru the channel probably weighs a bit more than grosgrain loops, if that matters to you.
6 - Yes
7 - Put a headhole and armholes so it'll slip over your front while you're resting, or when you first start hiking in the morning. Your backpack will insulate your back. When you get hot, just take it off w/o removing your backpack and stuff it in a sack. (Probably more trouble than it's worth, though...) Or just use it as a pillow. And maybe a super hero cape.

02-24-2008, 19:22

warbonnetguy

1. 40" or wider.

2. people argue for baffells in both directions, so either will work.

3. any conforming to the hammock should be done by the cut of the quilt, simply cinching the edge with shockcord only makes the edge conform to the hammock. this is what creates air gaps between the quilt and hammock and will make it much less efficient and less warm

4. mine is like that, it does a good job of keeping the long edge snug to the hammock, and the ability to slide the quilt towards either end is a big plus.

6. yes, if you are that concerned about weight.

7. it should be plenty long and wide enough to wrap around your upper torso like an indian blanket.

mine come to about 6" past my crotch, i find whatever i put under my knees adds alot of insul, and i use an 1/8"x60" pad doubled over under my legs as well.

good luck with the uq.

02-24-2008, 19:40

warbonnetguy

i see me and jeff posted simultaneously.

i found i was able to get a tighter fit having nothing at the ends, i cut them the correct width to begin with so there was no extra fabric to cinch or hang loose. this does seem to be a big factor in avoiding air gaps in the interior of the quilt, but i did end up putting a small (diameter of a nickel) draft tube running across either end to seal it off completely tight. i made them removeable via velcro, but since they weigh practly nothing, i can see leaving them on always for their added effiency they cause.

02-25-2008, 11:06

Schneiderlein

JJ and WBG,

your simultaneous posts now have me utterly confused. Maybe there are just so many different ways to do it that all work equally well that finding "the best way" to make a 3/4 UQ is inherently impossible.

My biggest question at the moment is the width. I was thinking an underquilt could be significantly narrower than a top or dual-purpose quilt. WBG's answer seems to indicate that, but JJ says make it pretty much the same width? I am currently using a 20" pad with two 5" wings in an SPE, so I only have 30" of insulated width under me at the moment. Do I really need an extra 15-18", or will an extra 10" suffice? Maybe I should just split the difference and make it 43 1/4".

The second thing I am wondering about is what WBG said about the quilt conforming to the hammock.

Quote:

Originally Posted by warbonnetguy

3. any conforming to the hammock should be done by the cut of the quilt, simply cinching the edge with shockcord only makes the edge conform to the hammock. this is what creates air gaps between the quilt and hammock and will make it much less efficient and less warm

I assume by "cut of the quilt" you do not simply mean to cut the fabric in a tapered shape, but to actually cut tapered panels to give it a 3D shape? This is an intriguing idea, and since I have a bit of cheap fabric left, I think it might be worth a try. What panel shape did you use on yours? Did you make the bottom of the quilt wider than the top?

JJ, I like the super hero cape idea. My daughter and I had a lot of fun with the down quilt I made yesterday. She likes poking her head through the head hole and then hiding under the quilt saying "You can't find me"...

02-25-2008, 17:22

Just Jeff

Yep - part of it is just that there are different ways to do the same thing. The extreme of this (at this point, at least) is the Speer SnugFit - it has a BUNCH of darts so you can't really NOT get a good fit. The JRB has no darts. The Kickass is somewhere in between - not really darts in the bottom, but it's shaped to the hammock b/c there are darts taken out of the sides. That's what WBG is talking about - if you shape it right, you don't need the JRB-style drawcords in the ends.

Re: width, I'd go more than 30". My half-underquilt is 39" wide...it's fine if I'm centered on it and on my back, but if I move around I have to reposition it. So you CAN make it more narrow and it'll work...just a matter of your personal style and how much weight you want to save. My next one will be ~45" wide.

02-25-2008, 18:52

warbonnetguy

i meant 40" for a minimum width, like if you are trying to save weight.

by cut, i just mean tapered shape, rather than rectangular/square. for instance, if the shock cord would cinch the end of the quilt to 24" wide, just make your shape 24" wide at that end, otherwise you will end up with a big air pocket right behind the shockcord.

the only darts i use are in the outer shell, this is so the outer shell can be larger as to not compress the insulation. since the uq will have thickness and be curved over the radius of the hammock (mainly side to side/width wise) the outer shell piece needs to be wider to account for this, if not, tensioning it will compress your loft. supposedly, the snug fit has darts on the inside piece as well so it will loft upward filling any air spaces in between the hammock and the uq (maybe youngblood can tell us). i found i could get a flat shape pretty darn snug if it was just the right shape, but like i said, i did add some thin draft tubes at the ends to seal it off completely.

02-25-2008, 20:16

Youngblood

2 Attachment(s)

Quote:

Originally Posted by warbonnetguy

i meant 40" for a minimum width, like if you are trying to save weight.

by cut, i just mean tapered shape, rather than rectangular/square. for instance, if the shock cord would cinch the end of the quilt to 24" wide, just make your shape 24" wide at that end, otherwise you will end up with a big air pocket right behind the shockcord.

the only darts i use are in the outer shell, this is so the outer shell can be larger as to not compress the insulation. since the uq will have thickness and be curved over the radius of the hammock (mainly side to side/width wise) the outer shell piece needs to be wider to account for this, if not, tensioning it will compress your loft. supposedly, the snug fit has darts on the inside piece as well so it will loft upward filling any air spaces in between the hammock and the uq (maybe youngblood can tell us). i found i could get a flat shape pretty darn snug if it was just the right shape, but like i said, i did add some thin draft tubes at the ends to seal it off completely.

There is some magic to differential shaping for an underquilt application. When you talk about differential shaping on a curve, or radius, you can have several classes of differential shaping. Most of us are familiar with an exact differential on a radius as shown in the first attached sketch. But there are some interesting properties one can obtain with various types of differential shaping. I have tried to demonstrate some of those that I could define in the second sketch. The SnugFit uses exaggerated differential shaping to allow it to be held snug against the underside of a hammock with minimum sensitivity to compression caused by that contact. That differential shaping is achieved fundamentally by curved baffles along the length of the underquilt and by radially spacing them along the width of the underquilt. To better fit in the crucial tush area and to get more uniform insulation, there are compound curves along both the length and the width as well as variable thickness in the baffles. All this calls for darts to make all that fit together. It gets rather complicated, but that is the general jest of the shaping.

Of course shaping is just part of it, because you still need to hold it up against the bottom of the hammock along as much of the surface as you can. That is where the full width suspension system comes into play.

02-25-2008, 20:28

skar578

excuse me, i have to find my rain remnants after youngblood's post.

yea, i have been planning a 1/2 length uq for quite some time, and still sketching plans i hope will be better then the last.

02-25-2008, 20:42

warbonnetguy

so, are their darts on the inside shell or is it flat?

ever notice the "negative curve" in a loaded hammock, basically under the knees, the hammock fabric tends to curve upward from the horizontal plane rather than downward like everywhere else. seems like it can curve upward by a couple inches, and can extend quite a ways up toward the suspension. does the snug fit still leave an air pocket under that spot or does it loft inward to fill the void? i felt like this was always the hardest spot to fit the uq to.

i agree about the suspension, never seemed like pull tabs on the corners would do an adequate job of doing that. (i saw the sf at td's, but can't remember the suspension)